Stops shuttles from bringing background turfs with them. (#15580)

code/game/objects/structures/morgue.dm

@@ -18,6 +18,7 @@
 	dir = EAST
 	density = TRUE
 	anchored = TRUE
+	obj_flags = OBJ_FLAG_MOVES_UNSUPPORTED
 	var/locked = FALSE
 	var/obj/structure/m_tray/connected = null
 	var/tray = /obj/structure/m_tray
@@ -143,6 +144,7 @@
 	anchored = TRUE
 	throwpass = TRUE
 	layer = TURF_LAYER
+	obj_flags = OBJ_FLAG_MOVES_UNSUPPORTED
 	var/obj/structure/morgue/connected = null
 
 /obj/structure/m_tray/Destroy()